Immune-Related Thyroiditis with Immune Checkpoint Inhibitors

Area of Science:

• Endocrinology
• Oncology
• Immunology

Background:

• Immune-related thyroiditis (irT) is a known side effect of immune checkpoint inhibitors (ICI).
• Current guidelines lack detailed characterization of irT's natural course and management.
• This study investigates the evolution and sequelae of irT in cancer patients treated with ICI.

Purpose of the Study:

• To investigate the natural course of immune-related thyroiditis (irT) in patients receiving immune checkpoint inhibitors (ICI).
• To describe the clinical presentation, evolution, and long-term outcomes of irT.
• To inform future management guidelines for irT.

Main Methods:

• Retrospective study of cancer patients treated with ICI between November 2014 and July 2016.
• Inclusion criteria: normal baseline thyroid function tests and development of thyrotoxicosis due to irT.
• Data collected on ICI type, cancer diagnosis, time to thyroid dysfunction, and treatment outcomes.

Main Results:

• 43 out of 657 patients (6.5%) developed irT, primarily with painless thyroiditis.
• Median time to thyrotoxicosis was 5.3 weeks; 67% were asymptomatic.
• Hypothyroidism developed in 84% of patients, often requiring long-term levothyroxine; combination ICI (ipilimumab + nivolumab) showed a faster onset of irT.

Conclusions:

• Immune-related thyroiditis (irT) typically presents with early, asymptomatic thyrotoxicosis followed by hypothyroidism.
• Long-term levothyroxine substitution is frequently required.
• Combination ICI therapy accelerates irT development, highlighting the need for vigilant thyroid function monitoring and updated clinical guidelines.